Evolving Management Practices for Early Sepsis-induced Hypoperfusion: A Narrative Review

Comparison of Early and Late Norepinephrine Administration in Patients With Septic Shock: A Systematic Review and Meta-Analysis

BACKGROUND

Vasopressor administration at an appropriate time is crucial, but the optimal timing remains controversial.

RESEARCH QUESTION

Does early vs late norepinephrine administration impact the prognosis of septic shock?

STUDY DESIGN AND METHODS

Searches were conducted in PubMed, EMBASE, the Cochrane Library, and KMbase databases. We included studies of adults with sepsis and categorized patients into an early and late norepinephrine group according to specific time points or differences in norepinephrine use protocols. The primary outcome was overall mortality. The secondary outcomes included length of stay in the ICU, days free from ventilator use, days free from renal replacement therapy, days free from vasopressor use, adverse events, and total fluid volume.

RESULTS

Twelve studies (four randomized controlled trials [RCTs] and eight observational studies) comprising 7,281 patients were analyzed. For overall mortality, no significant difference was found between the early norepinephrine group and late norepinephrine group in RCTs (OR, 0.70; 95% CI, 0.41-1.19) or observational studies (OR, 0.83; 95% CI, 0.54-1.29). In the two RCTs without a restrictive fluid strategy that prioritized vasopressors and lower IV fluid volumes, the early norepinephrine group showed significantly lower mortality than the late norepinephrine group (OR, 0.49; 95%, CI, 0.25-0.96). The early norepinephrine group demonstrated more mechanical ventilator-free days in observational studies (mean difference, 4.06; 95% CI, 2.82-5.30). The incidence of pulmonary edema was lower in the early norepinephrine group in the three RCTs that reported this outcome (OR, 0.43; 95% CI, 0.25-0.74). No differences were found in the other secondary outcomes.

INTERPRETATION

Overall mortality did not differ significantly between early and late norepinephrine administration for septic shock. However, early norepinephrine administration seemed to reduce pulmonary edema incidence, and mortality improvement was observed in studies without fluid restriction interventions, favoring early norepinephrine use.

Bay-117082 treats sepsis by inhibiting neutrophil extracellular traps (NETs) formation through down-regulating NLRP3/N-GSDMD

During the inflammatory storm of sepsis, a significant quantity of neutrophil extracellular traps (NETs) are generated, which act as a double-edged sword and not only impede the invasion of foreign microorganisms but also exacerbate organ damage. This study provides evidence that NETs can cause damage to alveolar epithelial cells in vitro. The sepsis model developed in this study showed a significant increase in NETs in the bronchoalveolar lavage fluid (BALF). The development of NETs has been shown to increase the lung inflammatory response and aggravate injury to alveolar epithelial cells. Bay-117082, a well-known NF-κB suppressor, is used to modulate inflammation. This analysis revealed that Bay-117082 efficiently reduced total protein concentration, myeloperoxidase activity, and inflammatory cytokines in BALF. Moreover, Bay-117082 inhibited the formation of NETs, which in turn prevented the activation of the pore-forming protein gasdermin D (GSDMD). In summary, these results indicated that excessive NET production during sepsis exacerbated the onset and progression of acute lung injury (ALI). Therefore, Bay-117082 could serve as a novel therapeutic approach for ameliorating sepsis-associated ALI.

METTL3-mediated TIM1 promotes macrophage M1 polarization and inflammation through IGF2BP2-dependent manner

Macrophage polarization and inflammation may play an important role in the development of sepsis. T-cell immunoglobulin mucin 1 (TIM1) has been demonstrated to promote macrophage inflammatory responses. However, whether TIM1 regulates macrophage polarization and inflammation to affect sepsis development remains unclear. Human monocytic leukemia cell line was induced into macrophages, followed by stimulated with LPS and IL-4 to induce M1 polarization and M2 polarization. The expression levels of TIM1, methyltransferase 3 (METTL3), and insulin like growth factor 2 mRNA binding protein 2 (IGF2BP2) were examined by qRT-PCR and western blot. IL-6, IL-1β, and TNF-α levels were tested by ELISA. CD86+cell rate was analyzed by flow cytometry. The m6A methylation level of TIM1 was assessed by MeRIP assay. The interaction of between TIM1 and METTL3 or IGF2BP2 was assessed by dual-luciferase reporter assay and RIP assay. TIM1 knockdown repressed LPS-induced macrophage M1 polarization and inflammation. In terms of mechanism, METTL3 promoted TIM1 expression through m6A modification, and this modification could be recognized by IGF2BP2. Besides, knockdown of METTL3/IGF2BP2 suppressed LPS-induced macrophage M1 polarization and inflammation, while this effect could be eliminated by TIM1 overexpression. METTL3/IGF2BP2/TIM1 axis promoted macrophage M1 polarization and inflammation, which might provide potential target for sepsis treatment.

Artificial Intelligence to Close the Gap between Pharmacokinetic/Pharmacodynamic Targets and Clinical Outcomes in Critically Ill Patients: A Narrative Review on Beta Lactams

Antimicrobial dosing can be a complex challenge. Although a solid rationale exists for a link between antibiotic exposure and outcome, conflicting data suggest a poor correlation between pharmacokinetic/pharmacodynamic targets and infection control. Different reasons may lead to this discrepancy: poor tissue penetration by β-lactams due to inflammation and inadequate tissue perfusion; different bacterial response to antibiotics and biofilms; heterogeneity of the host's immune response and drug metabolism; bacterial tolerance and acquisition of resistance during therapy. Consequently, either a fixed dose of antibiotics or a fixed target concentration may be doomed to fail. The role of biomarkers in understanding and monitoring host response to infection is also incompletely defined. Nowadays, with the ever-growing stream of data collected in hospitals, utilizing the most efficient analytical tools may lead to better personalization of therapy. The rise of artificial intelligence and machine learning has allowed large amounts of data to be rapidly accessed and analyzed. These unsupervised learning models can apprehend the data structure and identify homogeneous subgroups, facilitating the individualization of medical interventions. This review aims to discuss the challenges of β-lactam dosing, focusing on its pharmacodynamics and the new challenges and opportunities arising from integrating machine learning algorithms to personalize patient treatment.

Association between average mean arterial pressure and 30-day mortality in critically ill patients with sepsis and primary hypertension: a retrospective analysis

Sepsis and hypertension pose significant health risks, yet the optimal mean arterial pressure (MAP) target for resuscitation remains uncertain. This study investigates the association between average MAP (a-MAP) within the initial 24 h of intensive care unit admission and clinical outcomes in patients with sepsis and primary hypertension using the Medical Information Mart for Intensive Care (MIMIC) IV database. Multivariable Cox regression assessed the association between a-MAP and 30-day mortality. Kaplan-Meier and log-rank analyses constructed survival curves, while restricted cubic splines (RCS) illustrated the nonlinear relationship between a-MAP and 30-day mortality. Subgroup analyses ensured robustness. The study involved 8,810 patients. Adjusted hazard ratios for 30-day mortality in the T1 group (< 73 mmHg) and T3 group (≥ 80 mmHg) compared to the T2 group (73-80 mmHg) were 1.25 (95% CI 1.09-1.43, P = 0.001) and 1.44 (95% CI 1.25-1.66, P < 0.001), respectively. RCS revealed a U-shaped relationship (non-linearity: P < 0.001). Kaplan-Meier curves demonstrated significant differences (P < 0.0001). Subgroup analysis showed no significant interactions. Maintaining an a-MAP of 73 to 80 mmHg may be associated with a reduction in 30-day mortality. Further validation through prospective randomized controlled trials is warranted.

Hospital-Onset Sepsis Warrants Expanded Investigation and Consideration as a Unique Clinical Entity

Sepsis causes more than a quarter million deaths among hospitalized adults in the United States each year. Although most cases of sepsis are present on admission, up to one-quarter of patients with sepsis develop this highly morbid and mortal condition while hospitalized. Compared with patients with community-onset sepsis (COS), patients with hospital-onset sepsis (HOS) are twice as likely to require mechanical ventilation and ICU admission, have more than two times longer ICU and hospital length of stay, accrue five times higher hospital costs, and are twice as likely to die. Patients with HOS differ from those with COS with respect to underlying comorbidities, admitting diagnosis, clinical manifestations of infection, and severity of illness. Despite the differences between these patient populations, patients with HOS sepsis are understudied and warrant expanded investigation. Here, we outline important knowledge gaps in the recognition and management of HOS in adults and propose associated research priorities for investigators. Of particular importance are questions regarding standardization of research and clinical case identification, understanding of clinical heterogeneity among patients with HOS, development of tailored management recommendations, identification of impactful prevention strategies, optimization of care delivery and quality metrics, identification and correction of disparities in care and outcomes, and how to ensure goal-concordant care for patients with HOS.

Improving Intestinal Barrier Function in Sepsis by Partially Hydrolysed Guar Gum via the Suppression of the NF-κB/MLCK Pathway

Partially hydrolyzed guar gum (PHGG) protects against intestinal barrier dysfunction and can ameliorate some intestinal diseases. However, whether PHGG has a role in protecting intestinal barrier function (IBF) during sepsis remains unclear. This study aimed to investigate the role and probable mechanism of PHGG in the intestinal mucosa in sepsis. A rat sepsis model was constructed using cecal ligation and puncture (CLP). FITC-dextran 4 (FD-4) flux, serum inflammatory mediator levels, tight junction (TJ) levels, jejunum mucosa pathology, and epithelial intercellular junction ultrastructure were monitored to evaluate the effect of PHGG on IBF. Caco-2 monolayers were used to study the impact and mechanism of PHGG on lipopolysaccharide (LPS)-induced barrier dysfunction in vitro. The expression of zonula occludens protein-1 and occludin and the location of P65 were studied by immunofluorescence. Nuclear factor kappa B (NF-κB) and myosin light chain kinase 3 (MLCK) pathway-related protein expression was verified by quantitative reverse transcriptase polymerase chain reaction or western blotting. The results indicated that the jejunal mucosa structure was destroyed, the villi were disrupted and shortened, and neutrophil infiltration was evident in the septic rats. Compared to Sham group, spetic rats had increased Chiu's score, serum inflammatory mediator levels, and FD-4 flux but decreased TJ and gap junction density. In addition, the expression of MLCK, p-MLC, and TJ proteins and the expression of P65 in the nucleus were increased in septic rats. Furthermore, compared to those in the Control group, LPS-treated Caco-2 cells showed lower cell viability and transepithelial electrical resistance, while had higher FD-4 flux and the expression of MLCK, p-MLC, TJ proteins and P65 in the nucleus. PHGG pretreatment reversed the above effects induced by CLP or LPS treatment. Moreover, SN50, an NF-κB inhibitor, attenuated the above effects of LPS on Caco-2 cells. Overall, PHGG reduced inflammation, increased TJ protein expression and localization, and relieved damage to the TJ structure and intestinal permeability through suppression of the NF-κB/MLCK pathway. This study provides new insights into the role of PHGG in sepsis therapy.

The hospital frailty risk score effectively predicts adverse outcomes in patients with atrial fibrillation in the intensive care unit

Background

Atrial fibrillation (AF) and frailty are significant global public health problems associated with advancing age. However, the relationship between frailty and older patients with AF in the intensive care unit (ICU) has not been thoroughly investigated. This study aimed to investigate whether the hospital frailty risk score (HFRS) is associated with adverse outcomes in older patients with AF in the ICU.

Methods

This was the first retrospective analysis of older patients with AF admitted to the ICU between 2008 and 2019 at a tertiary academic medical center in Boston. The HFRS was used to measure frailty severity. The outcomes of interest were in-hospital and 30-day mortality and the incidence of sepsis and ischemic stroke.

Results

There were 7,792 participants aged approximately 80 years, almost half (44.9%) of whom were female. Among this group, 2,876 individuals were identified as non-frail, while 4,916 were classified as frail. The analysis revealed a significantly greater incidence of in-hospital (18.8% compared to 7.6%) and 30-day mortality (24.5% versus 12.3%) in the frail group. After accounting for potential confounding factors, a multivariate Cox proportional hazards regression analysis revealed that frail participants had a 1.56-fold greater risk of mortality within 30 days (95% CI = 1.38-1.76, p < 0.001).

Conclusions

Frailty is an independent risk factor for adverse outcomes in older patients with AF admitted to the ICU. Therefore, prioritizing frailty assessment and implementing specific intervention strategies to improve prognostic outcomes are recommended.

Complication Rates of Central Venous Catheters: A Systematic Review and Meta-Analysis

Importance

Central venous catheters (CVCs) are commonly used but are associated with complications. Quantifying complication rates is essential for guiding CVC utilization decisions.

Objective

To summarize current rates of CVC-associated complications.

Data Sources

MEDLINE, Embase, CINAHL, and CENTRAL databases were searched for observational studies and randomized clinical trials published between 2015 to 2023.

Study Selection

This study included English-language observational studies and randomized clinical trials of adult patients that reported complication rates of short-term centrally inserted CVCs and data for 1 or more outcomes of interest. Studies that evaluated long-term intravascular devices, focused on dialysis catheters not typically used for medication administration, or studied catheters placed by radiologists were excluded.

Data Extraction and Synthesis

Two reviewers independently extracted data and assessed risk of bias. Bayesian random-effects meta-analysis was applied to summarize event rates. Rates of placement complications (events/1000 catheters with 95% credible interval [CrI]) and use complications (events/1000 catheter-days with 95% CrI) were estimated.

Main Outcomes and Measures

Ten prespecified complications associated with CVC placement (placement failure, arterial puncture, arterial cannulation, pneumothorax, bleeding events requiring action, nerve injury, arteriovenous fistula, cardiac tamponade, arrhythmia, and delay of ≥1 hour in vasopressor administration) and 5 prespecified complications associated with CVC use (malfunction, infection, deep vein thrombosis [DVT], thrombophlebitis, and venous stenosis) were assessed. The composite of 4 serious complications (arterial cannulation, pneumothorax, infection, or DVT) after CVC exposure for 3 days was also assessed.

Results

Of 11 722 screened studies, 130 were included in the analyses. Seven of 15 prespecified complications were meta-analyzed. Placement failure occurred at 20.4 (95% CrI, 10.9-34.4) events per 1000 catheters placed. Other rates of CVC placement complications (per 1000 catheters) were arterial canulation (2.8; 95% CrI, 0.1-10), arterial puncture (16.2; 95% CrI, 11.5-22), and pneumothorax (4.4; 95% CrI, 2.7-6.5). Rates of CVC use complications (per 1000 catheter-days) were malfunction (5.5; 95% CrI, 0.6-38), infection (4.8; 95% CrI, 3.4-6.6), and DVT (2.7; 95% CrI, 1.0-6.2). It was estimated that 30.2 (95% CrI, 21.8-43.0) in 1000 patients with a CVC for 3 days would develop 1 or more serious complication (arterial cannulation, pneumothorax, infection, or DVT). Use of ultrasonography was associated with lower rates of arterial puncture (risk ratio [RR], 0.20; 95% CrI, 0.09-0.44; 13.5 events vs 68.8 events/1000 catheters) and pneumothorax (RR, 0.25; 95% CrI, 0.08-0.80; 2.4 events vs 9.9 events/1000 catheters).

Conclusions and Relevance

Approximately 3% of CVC placements were associated with major complications. Use of ultrasonography guidance may reduce specific risks including arterial puncture and pneumothorax.

Understanding How Clinicians Personalize Fluid and Vasopressor Decisions in Early Sepsis Management

Importance

Recent sepsis trials suggest that fluid-liberal vs fluid-restrictive resuscitation has similar outcomes. These trials used generalized approaches to resuscitation, and little is known about how clinicians personalize fluid and vasopressor administration in practice.

Objective

To understand how clinicians personalize decisions about resuscitation in practice.

Design, Setting, and Participants

This survey study of US clinicians in the Society of Critical Care Medicine membership roster was conducted from November 2022 to January 2023. Surveys contained 10 vignettes of patients with sepsis where pertinent clinical factors (eg, fluid received and volume status) were randomized. Respondents selected the next steps in management. Data analysis was conducted from February to September 2023.

Exposure

Online Qualtrics clinical vignette survey.

Main Outcomes and Measures

Using multivariable logistic regression, the associations of clinical factors with decisions about fluid administration, vasopressor initiation, and vasopressor route were tested. Results are presented as adjusted proportions with 95% CIs.

Results

Among 11 203 invited clinicians, 550 (4.9%; 261 men [47.5%] and 192 women [34.9%]; 173 with >15 years of practice [31.5%]) completed at least 1 vignette and were included. A majority were physicians (337 respondents [61.3%]) and critical care trained (369 respondents [67.1%]). Fluid volume already received by a patient was associated with resuscitation decisions. After 1 L of fluid, an adjusted 82.5% (95% CI, 80.2%-84.8%) of respondents prescribed additional fluid and an adjusted 55.0% (95% CI, 51.9%-58.1%) initiated vasopressors. After 5 L of fluid, an adjusted 17.5% (95% CI, 15.1%-19.9%) of respondents prescribed more fluid while an adjusted 92.7% (95% CI, 91.1%-94.3%) initiated vasopressors. More respondents prescribed fluid when the patient examination found dry vs wet (ie, overloaded) volume status (adjusted proportion, 66.9% [95% CI, 62.5%-71.2%] vs adjusted proportion, 26.5% [95% CI, 22.3%-30.6%]). Medical history, respiratory status, lactate trend, and acute kidney injury had small associations with fluid and vasopressor decisions. In 1023 of 1127 vignettes (90.8%) where the patient did not have central access, respondents were willing to start vasopressors through a peripheral intravenous catheter. In cases where patients were already receiving peripheral norepinephrine, respondents were more likely to place a central line at higher norepinephrine doses of 0.5 µg/kg/min (adjusted proportion, 78.0%; 95% CI, 74.7%-81.2%) vs 0.08 µg/kg/min (adjusted proportion, 25.2%; 95% CI, 21.8%-28.5%) and after 24 hours (adjusted proportion, 59.5%; 95% CI, 56.6%-62.5%) vs 8 hours (adjusted proportion, 47.1%; 95% CI, 44.0%-50.1%).

Conclusions and Relevance

These findings suggest that fluid volume received is the predominant factor associated with ongoing fluid and vasopressor decisions, outweighing many other clinical factors. Peripheral vasopressor use is common. Future studies aimed at personalizing resuscitation must account for fluid volumes and should incorporate specific tools to help clinicians personalize resuscitation.

Fluid resuscitation and relation to respiratory support escalation in patients with and without pulmonary hypertension with sepsis

STUDY OBJECTIVE

To compare guideline-based fluid resuscitation and need for respiratory support escalation in septic patients with pulmonary hypertension (PH) to those without PH.

DESIGN

Single-center, retrospective cohort study.

SETTING

Tertiary care academic medical center in Detroit, Michigan.

PATIENTS

Adult patients with or without PH hospitalized and diagnosed with sepsis from November 1, 2013 through December 31, 2019. Patients with sepsis were assigned to one of two groups based on a previous PH diagnosis or no PH diagnosis.

INTERVENTION

None.

MEASUREMENTS AND MAIN RESULTS

The primary outcome was incidence of respiratory support escalation within 72 h from sepsis time zero. Respiratory support escalation included high-flow nasal cannula, bilevel positive airway pressure, or intubation. One-hundred and four patients were included with 52 patients in each study group. Patients with PH were more likely to require escalation of respiratory support compared to non-PH patients (32.7% vs. 11.5%; p = 0.009). Fewer patients with PH received 30 mL/kg of crystalloid within 6 h of time zero compared with non-PH patients (3.8% vs. 42.3%; p < 0.001). Vasopressor initiation was more common in patients with PH compared with the non-PH group (40.4% vs. 19.2%; p = 0.018). PH diagnosis was the only independent predictor of respiratory support escalation.

CONCLUSIONS

During initial sepsis management when compared with patients without PH, patients with PH had increased instances of respiratory support escalation within 72 h of sepsis time zero despite lower fluid resuscitation volumes.